Apparatus for condensing and collecting mercury from gases containing the same together with corrosive substances



Dec. 8, 1931.

' K I. MARSHALL.= APPARATUS FOR CONDENSING AND COLLECTING MERCURY FROMGASES- CONTAINING THE SAME TOGETHER WITH CORROSIVE SUBSTANCES Filed July8, 1929 INVENTOR I flmeii I My); 6 Ira WWW ll-Ililllllll A TTORNEYS.

Patented Dec. 8, 1931 l 1 Tare"s T-orrlcaf KENNETHLMARSHALLOF IlosANGELES, CALIFORNIA, 'AssIGNon. r0 INTERNATIOLIAL "PRECIPITATIONCOMPANY, or Los ANGELES', CALIFORNIA, a CORPQRATIQN or- APPARATUS FORGONDENSING- AND COLLECTING MERCURY FROM GASES "CONTAINING THE SAME TOGETHER WITH CORR-QSIVE SUBSTANCE$ A ucauommd July 8,1929. Serial 'No.376,611.

This invention relates to apparatus for treatment of gases com ng fromretorts or furnaces for recovery of mercury from ores thereof, suchapparatus being for the purpose of condensing andcollectmg mercury fromsuch gases.

The main object of the invention isto pro- 1 vide an apparatus forthispurpose which will be resistant to the corrosive action of the 4 gasesor of the-fumes carried thereby; In the distillation and recovery ofmercury. from cinnabar and similar ores by the process nowv in use, theoreissub ected to heat treatment in furnacesin sujch manner that mercuryor compounds thereof pass off from thefurnace,

together with gasescontaining a considerable amount of corrosive agentsincluding sulphurous and/or sulphuric ,acid or anhydride. 7

To recover the mercury from such gases it is necessary to subject thesame to acooling and condensing operation to condense and I collect themercury. {For this purpose It has 7 been customary to use condensing andcollect-- 1mg means formed of terra cotta or similar corrosion-resistantmaterial. In order toincrease the elficiencyof cooling, it is desir'able to provide cooling means of metal so as to take advantage of thehigh heat conductivity of metals ascompared with terra cotta or similarmaterials, but the corrosive action of the mercury carryinggases hasheretofore preventedthe successful use of. metallic condensers and/orcollectors for this-purpose This corrosiveaction is ;particular-lyserious; during the stage of; cooling and conden sing. 1 when. thetemperature. has fallen below the, condensation temperature orfdew pointof the water. vapor present; as thetconden'sed water vapor is a materiala factor. in. the} corrosion.

I have found, tliatlby making. the condenseI and/or collector ofamalgamable metal," such 7 as copper, orbyproviding an iron or' steelcondenserwith a, coating of such amalgar .1 mable metal, the mercuryvapor condenses on the surface, formingan an'rialgam which protects themetal beneaththe amalgam surface from attack by the corrosive agentspresent in the gas. The corrosive actionis therefore practicallyeliminated by the formation of the amalgam coating which automatically1:

mentof the invention.

' In Fig. 1 of' the drawings, a mercury re tort is indicated at 1, saidretort being for example of the rotary kiln type as-shown or being forexample of the shaft type or any. other suitable type. Suitable meansindie.

cated at 2 for feeding mercury bearing one i to the retort andsuitable'means indicated at 3 being provided for heating the retort "tothe desired temperature, the gases passing from the retort and carrymercury vapor, together with products of combustion and sul-v 7 phurbearing gases, passed to a stack chamber 4 and thence through apipe 5 toa spray chamber 6 provided withmeans 7 for spray-- mg water into thegases and from said spray chamber the gasespasstlirough the condensingand/or collecting means which may, be" of any suitable type,but are inany case con structed more or-;les's completely of; metal. I Forexample, saidfcondensingand/ or collect.

ing means'may comprise a bafllej-lchamber 8,

a condenser of the'multi tubetypeindicated at 9 and a condenserYand/or'collector 1 0 V which 7 is adapted to operate effectively inseparating the condensed". mercury by cenr trifugal action. ,Fmm the1astma 1 ie ,c n-, r

- inthe spray chamber above the dew point of Water, the said spraychamber may made orother'amalgamable metal which is amalgamated eitherbefore matter the apparatus is put into operation, or the said parts maybe of iron or steel which is-copper coated and amalgamated as stated.

The condensing means 9 is shown as con sistiii'g of a plurality of tubesconnecting upper headerlG and lower header 17 and exposed'to coolingaction by contact with at- --mospheric air or by cooling fluidcirculated in contact with said pipes 15 in the usual mannerofmulti-tubular condensers and all parts of thiscondensing means areconstructed or. coated witlfanialgamable metal, such as copperyincasethe temperature in such apparatus is maintained below the dew point of.water vapor. It willbe understood that the several apparatuses 6,28 and9 serve as cooling or condensing and also as collecting means for anymercury which may be condensed-,"the collected material being carriedofi' through conduits 12; I prefer, however, to'provide 'formoreeffective cooling, condensing and/or collection by means of a ccn- 351itrifugal'cooler and/or. separator, such for example-as shown at"10 inFig. 1 and in Flgs' 2 and 8;

Said condensing and/or collecting apparatuscomprises an 'inletheader 19,a plurality ofcoolerand separator tubes 20'commun'icating at theirupper. ends with thc'inlet header 19.through"passage means 21 providedwith deflectors'22' or: otherwise formed to introducethegases into thetubes 20 with atan- -gentialor vortical movement. The tubes 20open-fiattlreir 'lower ends into'a receiving chamber-24whi'ch may beprovided with an overfi'ow pipe25so located that a body ofeondensedliquid is maintained within the re- "-ceptacle24', forming aseal 'forthe lower ends of the'separator tubes. Outlet passages 26 areprovided at the upper ends'of the separato-r tubes and located axiallytherein so'that the efiluent gases from. which the mercury has beenseparated, by the centrifugal action in th-separator tubes can pass outthrough these passages 26 to the outlet fiue- 11. It will be understoodthat'instead of this specific form of-condensing and/or collectingmeans, v any other' suitable condensing and/or colleetmg means maybeused in which the gases or:vapors are subjected to centrifugal actionllT COntaCb w1th the walls otthe separator tubes so as to increasetheefficiency of cool- -'*in-gzand/orcollection*,s:and that any: one ormore of the types of cooling and/or condensing means may be used,without the others. In any case, however, all the metallic parts of suchcoolingand/or collecting means, as well as'all metallic'flues connectingsame will be made of or coated with copper or other amalgamable metal.

If desired, an electrical precipitator canbe used in place of or inaddition to any of the cooling and separating means above described,forexample, as shownin Fig. 4, I may provide two electricalprecipitators 30 and 31 connected in series, the precipitator 30being:providedwith an inlet flue 32 for conducting thereto the gasespassing from the mercury producing retort or furnace and with an outletflue 33 forconducting the gases from the precipita'tor 30 to suitablecooling means indicated at34'which may, for exam )le be a s ra chamber;From said coolin b means said gases are conducted by a flue 35 to theinlct-ofthe-electrical precipitator 31, the outlet 36of'saidprecipitator leading to a stack or other means for dispositionofthe waste gases. The precipitators 30 and 31 may be of any usual orsuitableconstruction being herewith shown as of-the multiple pipe typeeach comprising a plurality of pipes 39 serving as collecting electrodesand with discharge electrodes 40 formed as'wires orrods extendingaxially in the respective pipes and mounted on suitable insulatingmeans,- said discharge electrode being-connected by wires 41- and 42 tothe usual means for supplying rec tifier current'thereto at-sufiicientlyhigh potential difference to maintain silent discharge between the wires4: or within the tubes 39 and thereby cause precipitation of suspendedmaterial on the-walls 'of'saidtubes. The precipitator 30 maybemaintained at a temperaturc'above the dew "point of water andinthat'case it may be constructed of iron or steel in the usual manner,and the precipitator 31 may be maintained below the dew point of waterand may be constructed of copper or other amalgable metal 'or lined withsuch metalin the manner above described, both the discharge andcollecting electrodes being preferably composed of orcoated with suchmetal. The particular application of my in vention :in connection withan electrical apre cipitatoris not specifically claimed herein as" itforms the subject matter of my application Ser. No. 346,808, filed March13', .1929.

If desired, the surface of copper or similar metal maybe amalgamatedbefore assembling into any of the forms of=apparatus above describedor-before the apparatus is putinto operation, but in general th1s is notnecessary as: I have found'that the amalgamation of the-coppersurfaceexposed to the gases containing mercury vaponta'kes place automaticallyin the operation of the apparatus as a condenser and/or collector. Insuch :oper--* ation the hot gases PEISSIDg FIOlH the mercury furnaces,(for example, a furnace of the rotary kiln type in which the mercury oreis subjected to heat treatment by the action of combustion gasesproduced by combustion of a suitable fuel with air) contains in additionto the residual air and products of combustion, oxidization products ofsulphur, and mercury vapor and/0r mercury compounds. Such gases cominginto contact with the copper or amalgamable metal surfaces of thecondenser rapidly deposit a coating of mercury thereon, forming asurface which is resistant to the action. of the corrosive elements ofthe gases and in the same manner the ac- 1 tion of the gases maintainssuch surfaces in an amalgamated state and thereby resistant to thecorrosiveelements present during the operation of the apparatus.

I claim: V

2 1, An apparatus for condensing and collecting mercury from gasescontaining the same together with corrosive materials, comprisingpassage means having the walls thereof provided with surfaces ofamalgamated 2 copper. a V

2. An apparatus for condensing and collecting mercury from gasescontaining the same together with corrosive materials, comprisingpassage means having the walls there- 3 of formed of iron provided withan internal coating of copper.

3. An apparatus for condensing and collecting mercury from gasescontaining the same together with corrosive materials, comprisingpassage means having the portions thereof which are exposed to saidgases, formed of iron provided with an amalgamated coating of copper. iIn testimony whereof I have hereunto sub- 40 scribed my name this29th'day of June, 1929.

KENNETH I. MARSHALL.

